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Username Post: Which cylinder        (Topic#365516)
Pmeeee 
Newbie
Posts: 3

Reg: 06-14-21
06-14-21 10:19 AM - Post#2821594    

I bought a taken apart gen vi 454 L21 vortec engine block, crank, n rods/pistons. The guy who took it apart didn't label what cylinder rods/pistons came out of.
The rods/pistons are still assembled together but how do I tell what cylinder each came out of? There are many factory marks on inside of pistons but nothing obvious (to me). On the rod cap sides(both upper n lower)they have unique stamping marks.They are:
T053
V028
V272
X225
M029
L290
X254
L147
What does the stamping mean? Hopefully that translates to a certain cylinder or something.
Thanks for your help!



 


paulo57509 
Senior Member
Posts: 510

Loc: CA
Reg: 07-18-00
06-14-21 02:07 PM - Post#2821600    
    In response to Pmeeee

I don't think you can really tell for sure which piston came out of which bore.

I "think" the tang side of the bearing faces the pan rail (you should also be able to use the chamfer on the big end to tell which way it matches with the radius on the crank journal); match this with the piston notch (or other ID) that denotes "front" and you at least know which bank they came out of.

Are you trying to put the used parts back into the un-machined bores? I think you have to ask, why was the engine torn down in the first place. It might be a waste of time putting the old parts back in.

1987 IROC-Z 5.0L
1992 Lumina Euro 3.1L
2003 GMC Safari


Edited by paulo57509 on 06-14-21 02:08 PM. Reason for edit: No reason given.

 
steve65 
"6th Year" Gold Supporting Member
Posts: 1022
steve65
Age: 63
Loc: New Westminster BC
Reg: 09-25-13
06-15-21 05:48 AM - Post#2821622    
    In response to Pmeeee

Check the area where the cap and connecting rod meet. There should be a number stamped in the flat spot (1-8) that should indicate the bore they go in?
At least they are on my stock/original 454.
After market or replacement parts...maybe not.
Just something to look for.
Steve

Steve Duncan
66 Impala 2dr Coupe
Not sure of color yet
work in progress



 
Algoma56 
Contributor
Posts: 736

Loc: Sault Ste. Marie, ON, Can...
Reg: 03-14-05
06-15-21 07:19 AM - Post#2821626    
    In response to paulo57509

Go along with Paolo's advice. Main thing, is the rod caps are still on their respective rods.



 
Pmeeee 
Newbie
Posts: 3

Reg: 06-14-21
06-15-21 01:50 PM - Post#2821642    
    In response to Algoma56

Thanks for the tips.
They come from a gm motor part# 19207556 but I can't find any specs on the motor other than 7.4L 454 vortec. I'm told it's from an industrial natural gas generator and no idea why disassembled. I want to re-ring and put back together.
Anyone know specs of this engine?



 
paulo57509 
Senior Member
Posts: 510

Loc: CA
Reg: 07-18-00
06-15-21 04:54 PM - Post#2821651    
    In response to Pmeeee

  • Pmeeee Said:
Thanks for the tips.
They come from a gm motor part# 19207556 but I can't find any specs on the motor other than 7.4L 454 vortec. I'm told it's from an industrial natural gas generator and no idea why disassembled. I want to re-ring and put back together.
Anyone know specs of this engine?



I think you can start with generic, virgin 454 bore x stroke specs:

454 = 4.250" x 4.00"

I'd measure the bores to see what they measure. It would be a total waste of time to re-ring a worn block.

Just some perspective:
https://www.chevelles.com/threads/max-cylinder- wea...

Grumpy or others should have some solid advice on what the wear threshold should be.


1987 IROC-Z 5.0L
1992 Lumina Euro 3.1L
2003 GMC Safari


 
rumrumm 
"20th Year" Silver Supporting Member
Posts: 2115
rumrumm
Loc: Macomb, IL
Reg: 10-18-01
06-19-21 03:41 PM - Post#2821817    
    In response to paulo57509

I was always told that .005 wear was the maximum amount of cylinder wear you would want to have to put an engine back together. Anything more, and it would be advisable to have it bored. I would suggest taking it to a machine shop and having the cylinders checked for wear and the rods checked to see if any of them need to be resized.

Lynn

"There's no 12-step program for stupid."


383 sbc, Eagle, AFR, SRP, CompCams, Edelbrock, FiTECH. Dyno #'s: 450 hp @ 5700, 468 lb. ft. of torque @ 4300.



Edited by rumrumm on 06-19-21 03:42 PM. Reason for edit: No reason given.

 
bobb 
Super Senior Member
Posts: 5835

Loc: paradise
Reg: 09-05-03
06-27-21 10:16 AM - Post#2822183    
    In response to Pmeeee

you better make real sure that all the main and rod caps are where they are supposed to be. look at the honing marks with the cap installed, they must match. then stamp or engrave numbers on them for a permanent record.

70 L camino, grampa engine, g-force 5 spd, road rage suspension. Pray first before all else fails.


 
Shepherd 
Frequent Contributor
Posts: 2265

Loc: Lake George, NY
Reg: 11-11-15
06-27-21 01:32 PM - Post#2822191    
    In response to rumrumm

.005 cylinder wear is excessive. That is adding to to the piston to wall clearance which will now cause excessive piston rocking.



 
Pmeeee 
Newbie
Posts: 3

Reg: 06-14-21
06-30-21 10:04 AM - Post#2822370    
    In response to Shepherd

The worst cylinder is 0.0025 worn. Should be good to go with just flex hone and no boring, right??



 
IgnitionMan 
Valued Contributor
Posts: 3897

Reg: 04-15-05
06-30-21 01:46 PM - Post#2822390    
    In response to Pmeeee

I would say the .0025 is too large, ring sealing issues come forth. The issue is the taper in the bore not working well with the ring seal.

I bore at .002 for nice cast pistons, and I try to never use forged pistons in anything street wise.



 
paulo57509 
Senior Member
Posts: 510

Loc: CA
Reg: 07-18-00
07-01-21 08:03 AM - Post#2822441    
    In response to Pmeeee

  • Pmeeee Said:
The worst cylinder is 0.0025 worn. Should be good to go with just flex hone and no boring, right??



IMO, if you're just going to put it back together, leave the bore alone. No berry hone, no nothing.


1987 IROC-Z 5.0L
1992 Lumina Euro 3.1L
2003 GMC Safari


 


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